When running a multiple dump tank operation and using multiple jet siphons, a need often arises for another pumping unit to supply some of the jet siphons - simply due to pump capacity issues. This issue most commonly occurs when a smaller capacity pumper (1,250 gpm or less) is used as the dump site pumper and fire flows are needed in the 1,000 gpm range. Because jet siphons consume pump capacity, a 1,000 gpm pumper may struggle to pump 1,000 gpm to the fire and supply two jet siphons at the same time. At this water supply drill in Ottawa, Kansas - a grass fire rig was used to supply a jet siphon, thus freeing the 1,000 gpm dump site pumper to obtain a support a higher fire flow.
Cutler Grass 3571 drafts from a dump tank and supplies a jet siphon (orange) hose. This allowed the dump site pumper to focudirect more of its pump capacity to the fire flow.
The grass rig and supply pumper (yellow) operate this 3-tank set-up and supply water to the attack pumper (red).
Pomona Engine 3952 (1,000 gpm) operated as the dump site pumper.